Niche Level Research Articles

Stochastic dynamics of interacting haematopoietic stem cell niche lineages.

Since we still know very little about stem cells in their natural environment, it is useful to explore their dynamics through modelling and simulation, as well as experimentally. Most models of stem cell systems are based on deterministic differential equations that ignore the natural heterogeneity of stem cell populations. This is not appropriate at the level of individual cells and niches, when randomness is more likely to affect dynamics. In this paper, we introduce a fast stochastic method for simulating a metapopulation of stem cell niche lineages, that is, many sub-populations that together form a heterogeneous metapopulation, over time. By selecting the common limiting timestep, our method ensures that the entire metapopulation is simulated synchronously. This is important, as it allows us to introduce interactions between separate niche lineages, which would otherwise be impossible. We expand our method to enable the coupling of many lineages into niche groups, where differentiated cells are pooled within each niche group. Using this method, we explore the dynamics of the haematopoietic system from a demand control system perspective. We find that coupling together niche lineages allows the organism to regulate blood cell numbers as closely as possible to the homeostatic optimum. Furthermore, coupled lineages respond better than uncoupled ones to random perturbations, here the loss of some myeloid cells. This could imply that it is advantageous for an organism to connect together its niche lineages into groups. Our results suggest that a potential fruitful empirical direction will be to understand how stem cell descendants communicate with the niche and how cancer may arise as a result of a failure of such communication.

Suitable, reachable but not colonised: seasonal niche duality in an endemic mountainous songbird

The realized distribution of animals is often delimited by climatic factors which define, next to the specific habitat and food availability, their species-specific potential distribution. We studied the environmental limi- tations affecting the realized breeding and wintering dis- tributions of the Citril Finch (Carduelis citrinella), one of the few endemic bird species of European mountain ranges. To assess the environmental limits that shape the seasonal distribution, we used species distribution models (SDMs) derived from macroclimate in combination with land cover information. Our data suggest a high congruence between the potential modelled breeding distribution of the Citril Finch and the currently known breeding sites, indicating a high level of niche filling. The unusual absence in several suitable breeding habitats at the eastern and northern range limit (Eastern Alps, Carpathians, Bavarian Forest, Harz Mountains, Fichtelgebirge, Krkonose Mountains) is likely linked to a combination of both missing resources and restricted physiological migration capacities from the available wintering grounds. Since the accomplished migratory distances hardly exceed more than 500 km, it seems likely that the distance to the main wintering areas is too large for exceeding eastern and northern range limits. We discuss the differences in SDM outcomes when including distal predictor variables instead of using proxi- mal predictors alone, and highlight the importance of considering a seasonal niche duality to gain more insights into complex range effects in species with seasonal ranges.

Exploring the market for Compressed Natural Gas light commercial vehicles in the United Kingdom

This paper examines the potential market for natural gas as a transportation fuel in the light commercial vehicle sector in the United Kingdom. In order to understand this market and identify barriers to growth and possible solutions interviews were conducted with a number of professionals with experience in this market. These interviews were open and exploratory enabling the application of grounded theory techniques in analysis. Clear priorities for potential users were cost and carbon reduction and the main constraint a lack of refuelling infrastructure. Small scale and low cost policy interventions were identified, at national level including maintaining tax differentials; easing payload restrictions; and limited support for refuelling facilities alongside local policy initiatives, for example, restoring the exemption from the London Congestion Charge for gas vehicles, that could help to kick-start the market at least at a niche level.

Using lead market factors to assess the potential for a sustainability transition

This paper considers how the lead market concept can contribute towards analysing system transformation as described by the multi-level perspective (MLP). Lead market arguments for the export potential of eco-innovations can provide an argument for policy support for environmental niches. International policy diffusion and learning across countries on the level of niche–regime interaction can improve the legitimacy of supporting policies. We propose how eco-innovation can be framed within an integrated MLP-lead market approach. Eco-innovations address two classes of regimes (infrastructure and eco-efficiency), which are likely to follow different transition pathways. The use of indicators for lead market factors for empirically analysing the opportunities for system transformation in the MLP framework is assessed. Indicators for the lead market factors can be attributed to the MLP. However, some of the indicators are more general in nature and do only indirectly point towards system transformation towards eco-innovations.

Should small exporting technology enterprises use niche, strategic alliances, or both?

This study compares and evaluates the niche strategy as well as the alliance strategy for small exporting technology enterprises (SETEs). The literature indicates that either strategy is effective, as both serve the same purpose of relaxing resource constraints. However, the results of this study indicate that SETEs that adopt both strategies simultaneously perform significantly better than those that adopt only one strategy so one strategy does not duplicate the other. Moreover, SETEs cannot maximise returns either if they rely heavily on both strategies simultaneously. The optimal strategy for SETEs lies either on the combination of high level of niches and low level of alliances or on the combination of low level of niches and high level of alliances.

An exergy-based analysis of the co-evolution of different species sharing common resources

We consider a set of species feeding on the same exergy resources. The balance equations for the allocation of such resources among the species result in a set of non linear differential equations describing the dynamics of each population. We address the important question of optimal exploitation of the incoming exergy resource at the species- and ecological niche level: more specifically, after a formal definition of the exergy effectiveness of the conversion for the overall system and for each species, we search for the – unique or multiple – set of values of the model parameters that may lead to a sustainable situation in which all of the species survive and – together – optimally exploit the incoming exergy flux. The analytical results will be discussed both qualitatively and, for a 2-species case, quantitatively.

Sustainable energy transitions in emerging economies: The formation of a palm oil biomass waste-to-energy niche in Malaysia 1990–2011

The economic development in emerging economies in Southeast Asia has significantly increased the use of fossil fuel based energy. This has severe implications for global climate change, and against this background, scholars within the sustainable transition tradition have taken an interest in addressing how transitions towards more sustainable development pathways in this region may be achieved. This paper contributes to the abovementioned literature by examining the conducive and limiting factors for development and proliferation of a palm oil biomass waste-to-energy niche in Malaysia during the period 1990–2011. Rising oil prices, strong pressure on the palm oil industry from environmental groups, and a persisting palm oil biomass waste disposal problem in Malaysia appear to have been conducive to niche proliferation, and on top of this national renewable energy policies and large-scale donor programmes have specifically supported the utilisation of palm oil biomass waste for energy. However, in spite of this, the niche development process has only made slow progress. The paper identifies reluctant implementation of energy policy, rise in biomass resource prices, limited network formation and negative results at the niche level, as the main factors hindering niche development.

Short-term sonic-hedgehog gene therapy to mitigate myelosuppression in highly irradiated monkeys: hype or reality?

The protection of hematopoietic stem and progenitor cells and their environment is required for recovery from radiation-induced (RI) myelosuppression. To achieve this goal, we propose a new gene therapy strategy based on local and short-term synthesis and expression of Sonic hedgehog morphogene (Shh) at the niche level. We investigated the hematopoietic response of 8 Gy gamma-irradiated monkeys to a single intra-osseous injection of multipotent mesenchymal stem cells (adipocyte-derived stem cells/ASC) transduced with a Shh pIRES2 plasmid (3+/-0.4 × 10(6) cells/kg on day (D) 2; n=4). Control animals were injected with mock-ASCs (n=4). Two controls died from radiation toxicity on D19 and D196, whereas all Shh-ASC treated monkeys fully recovered. Thrombocytopenia (4.75+/-1.8 days versus 10+/-2.2 days, platelet count <20 × 10(9)/L), neutropenia (14.2 +/-1 days versus 17.7 +/-2.6 days, ANC count<0.5 × 10(9)/L) and anemia (15.5 +/-3.6 days versus 50.7 +/-31 days, Hb less than 10 g/dL) duration were reduced in Shh-ASC animals. Areas under the curve of platelets (P<0.05), ANCs (P=0.06) and RBC/Hb between D0 and D30 were higher in Shh-ASC injected animals. Globally this study suggests that Shh may represent a new factor to counteract RI-myelosuppression.

Effects of under-development and oil-dependency of countries on the formation of renewable energy technologies: A comparative study of hydrogen and fuel cell technology development in Iran and the Netherlands

Countries face many problems for the development of renewable energy technologies. However these problems are not the same for different countries. This paper provides insight into the development of Hydrogen and Fuel Cell Technology (HFCT) in Iran (1993–2010), as an alternative for increasing sustainability of energy system in long-term. This is done by applying the Technological Innovation System (TIS) approach and studying the structure and dynamics of seven key processes that affect the formation of HFCT TIS. Thereafter, the pattern of HFCT development in Iran is compared with the Netherlands, using a multi-level perspective. Then, it is shown that under-development and oil-dependency, which are two macro-economic factors at landscape level, can explain the main differences between these countries at regime and niche levels. This means that macro-economic factors cause Iran and the Netherlands to experience different ways for the development of HFCT.

The impact of niche green developments in transforming the building sector: The case study of Lochiel Park

Energy use in residential buildings is a significant contributor to global carbon emissions. The South Australian Government responded to concern for anthropogenic greenhouse gas emissions by creating a model development of near zero energy homes in a near zero carbon impact estate. The creation of the Lochiel Park Green Village challenged a collective of industry experts and policy makers to set objectives, performance targets and regulatory guidelines outside existing institutional and professional norms. Literature suggests that the creation of niche events can help the transition away from dominant technologies, practices and beliefs, and lead to organisations embracing new tools, construction practices, technologies, standards and policies. By applying a multi-level socio-technical framework, and utilising evidence collected from a series of interviews with key government and industry leaders, this paper examines how, under the influence of landscape pressures, structural change at the regime level can come from the incubation of ideas and experiences at the niche level. The available evidence finds that the creation of the Lochiel Park Green Village has allowed many individuals and organisations to gain a more detailed and practical understanding of sustainable housing, and has given organisations the confidence to change industry practices, government policies, and regulatory standards.

The role of the complementary sector and its relationship with network formation and government policies in emerging sectors: The case of solar photovoltaics between 2001 and 2009

Understanding the role of government policies in promoting the introduction of renewable technologies can help to catalyze the transition toward a more sustainable energy system. The literature on technological transitions using a multi-level perspective suggests that the co-evolution of the niche market (the new technology) and the complementary regime may have an important role to play in shaping this transition. This paper provides a quantitative analysis of the interactions between different types of solar photovoltaic (PV) networks at the niche level, the complementary semiconductor sector at the complementary regime level, and the solar PV policies in 14 different countries. Using three equations for solar PV knowledge generation, manufacturing, and deployment, we investigate linkages between feed-in-tariff (FiT) and renewable portfolio standard (RPS) policies, network development, and the existence of a complementary sector. The empirical findings show that the complementary sector is an important determinant in solar PV deployment and manufacturing and network effects are dependent on the strength of the complementary sector in solar PV deployment and manufacturing. Feed-in-tariff and renewable portfolio standards are associated with solar PV diffusion and not with manufacturing. Finally, domestic government policies promoting renewable energy markets, which often lead to domestic electricity rate increases, have contributed to increased manufacturing capabilities internationally, including also in countries without a strong complementary sector, such as China, through the channel of manufacturing collaborations from countries with a strong complementary sector.

TOWARDS A REGIME CHANGE IN THE ORGANIZATION OF THE SEED SUPPLY SYSTEM IN CHINA

SUMMARYThis paper explores changes in the organization of seed supply in China over the last decade by means of a multi-level institutional analysis. At the landscape level, the implications for China of the regulation of plant genetic resources through various international treaties and conventions are reviewed in the light of the evolution of the global seed industry. At the regime level, the transition in the Chinese context to market-based seed supply and the development of commercial and public seed sectors are examined. The study then analyses trends in seed supply at the niche level, with reference to participatory maize (Zea mays L.) breeding in three provinces in southwest China where high rural poverty persists. This work offers radical novelty in variety development and seed provision on behalf of smallholder farmers. However, a series of technical, organizational and market ‘mismatches’ are demonstrated within the existing seed regime. The participatory work emphasizes breeding for diverse cultivars adapted to specific ecosystems but these are prevented from reaching commercial markets by existing varietal testing procedures. Participatory breeding has potential to address farmers’ varietal needs as agriculture modernises and to support the public function of research institutes, but within mainstream intellectual property regimes the public value of participatory breeding cannot be accommodated adequately. Yet, when coupled to institutional innovations for recognising intellectual property and sharing benefit among all those who contribute, participatory breeding may initiate a powerful dynamics for change within seed regimes and a sui generis seed system suited to the Chinese context.

Trait but not species convergence during plant community assembly in restored semi‐natural grasslands

Community assembly or succession was traditionally thought of as being deterministic and directional, leading to a clearly defined climax state. The alternative view, however, keeps gaining attention. This view states that community assembly is influenced by historical processes, where differences in the sequence and timing of species arrival result in distinct communities. Here we tested the hypothesis that both views are valid, but at a different level, with increasing dissimilarity in species composition among sites with increasing age (divergence), caused by historical processes (priority effects), and with increasing similarity in mean trait composition (convergence) among sites, indicating a directional development at the niche level. We surveyed a chronosequence of restored semi‐natural grassland patches on former pine plantations over seven restoration age classes, covering 22 grasslands. Pairwise multivariate distances were calculated between the different grassland patches based on species abundance on the one hand, and on mean community trait values for 28 plant life history traits on the other. Trait composition showed a clear decrease in multivariate distance with increasing restoration age, indicating trait convergence through time. At the species level, we found no evidence of convergence through time, with even a trend towards divergence. Furthermore, spatial variation and environmental heterogeneity were found to remain constant through time. These results confirm our hypothesis. At the trait level, limited niches occur, only filled by species having the appropriate traits, resulting in a clear deterministic model of assembly. Species identity, on the contrary, has no role in this niche filling. The first appropriate species to reach a restoration site will be most likely the ones that get established, resulting in divergence of the species composition among restored grasslands.

Governing the transition of socio-technical systems: A case study of the development of smart grids in Korea

This paper examines the motivations, processes and outcomes of the development of smart grids in South Korea through the perspectives of governance and innovation systems. Drawing on desktop research and semi-structured interviews, this paper has two major findings. First, the development of smart grids in Korea has been shaped by various factors including macroeconomic policy, the role of the government, and experimentation. The complex interactions between these factors at the landscape, regime and niche levels has impacted on the development of smart grids. Second, while Korea's government-led approach has its strengths in driving change, it has also exposed weaknesses in the country's ability to mobilise the private sector and consumer participation. Major obstacles including partial electricity market reform and public distrust exist. A systemic perspective is needed for policy in order to accommodate the changes required for smart grid development. Regulatory reforms, particularly price-setting mechanisms, and consumer engagement are priority areas for policy change.

Innovation projects and visions on the future: ambition and commitment in the Agropark case

Abstract Since the 1980s, Dutch agricultural policy focuses on changing the agricultural sector into a more sustainable sector. In this article we explore an Agropark visioning initiative and four Agropark innovation projects to provide further understanding in how visions on the future influence innovation projects. In addition we question which innovation strategies actors adopt to ensure both high levels of ambition and high degrees of commitment towards the innovation Agropark. Our study shows that future visions can lead to high expectation within the policy and public domain which creates both opportunities and tensions for innovation projects. Furthermore, the analysis shows that each Agropark innovation project applied specific innovation strategies that suited their distinct context and network of actors. Furthermore, actors within the innovation projects contextualise and thereby re-design future visions into local visions. They thus create a more viable design but at the same time dilute initial ambitions. Recognising these tensions and opportunities in their different guises, and making them part of the learning process time and again, both at regime level and at niche level, assist actors that aspire to guide far-reaching innovations.

Transition towards sustainable material innovation: evidence and evaluation of the Flemish case

In this article, we focus on testimonies on recent sustainable material innovations in 15 Flemish production firms. We look at evidence of transition towards sustainable material innovation, considering: (1) how material innovation can improve the sustainability of products and processes with respect to people, planet and profit and (2) what are stimulating and hindering factors met when adopting sustainable material innovation. Trends observed from assessing the sustainability features of the individual material innovation cases are presented in 3P evaluation grids. A meta-analysis of the testimonies considers drivers and barriers for sustainable material innovation on the level of technological niches, socio-technical regimes and socio-technical landscapes, referring to the multi-level perspective used in transition literature. It was found that the interplay between these levels has been key in all the assessed cases. Stimulated by the increasing scarcity and rising prices of raw materials, a growing eco-sensitivity among their customers, and the downright need for economic survival, production companies turn to look for more innovative ways of using materials in order to arrive at more sustainable products and production processes.

Comparative microbial sampling from eutrophic caves in Slovenia and Slovakia using RIDA ®COUNT test kits

RIDA®COUNT test plates were used as an easy-to-handle and rapid indicator of microbial counts in karst ecosystems of several caves in Slovakia and Slovenia. All of the caves had a high organic input from water streams, tourists, roosting bat colonies or terrestrial surroundings. We sampled swabs, water and air samples to test robustness and universality of the RIDA®COUNT test kit (R-Biopharm AG, Germany, http://www.r-biopharm.com/) for quantification of total bacteria, coliforms, yeast and mold. Using data from swabs (colony-forming units CFU per cm 2 ) we proposed a scale for description of biocontamination level or superficial microbial load of cave niches. Based on this scale, surfaces of Ardovska Cave, Drienovska Cave and Stara Brzotinska Cave (Slovakia) were moderately colonized by microbes, with total microbial counts (sum of total bacterial count and total yeast and molds count) in the range of 1,001-10,000 CFU/100 cm 2 , while some surfaces from the show cave Postojna Cave (Slovenia) can be considered highly colonized by microbes (total microbial counts ≥ 10,001 CFU/100 cm 2 ). Ardovska Cave also had a high concentration of airborne microbes, which can be explained by restricted air circulation and regular bat activity. The ratio of coliform to total counts of bacteria in the 9 km of underground Pivka River flow in Postojna Cave dropped approximately 4-fold from the entrance, indicating the high anthropogenic pollution in the most exposed site in the show cave. The RIDA®COUNT test kit was proven to be applicable for regular monitoring of eutrophication and human influence in eutrophic karst caves.

Clashes as potential for innovation in public service sector reform

PurposeThe purpose of this study is to examine the ongoing dynamics of the public service sector reform through an embedding process of a municipal enterprise from the field of basic social and health care services – a pilot model in Finland.Design/methodology/approachThe framework of a multi‐level perspective on transitions is used to describe the change process. At the lowest level of this perspective are the experimental niches acting as “seeds of change” represented by the case organisation, a municipal enterprise operating in the basic social and health care sector. The data consist of 16 thematic interviews with the key persons of the operating system, analysed with the principles of content analysis.FindingsThe examination uncovers diverse pressures affecting niche level innovations and manifesting as clashes and controversies between old and new ways of thinking, but these clashes can also act as a platform for innovations when opened up, analysed and facilitated.Practical implicationsClashes that appear in societal transition processes and regime changes, both in the regimes and also on the organisational level, should not be seen solely as bottlenecks, because they can act as innovation potential when opened up and facilitated. This implies the need for not only new technological, service‐related and organisational innovations in the public sector reform, but also innovative practices, “second level innovations”.Originality/valueThis paper contributes to the discussion on the ongoing change processes in the reform of the social and health care sector, emphasising emerging clashes not only as obstacles but opportunities.

Iceland’s hydrogen energy policy development (1998–2007) from a sociotechnical experiment viewpoint

From this case study of the Icelandic case, a real-life scale sociotechnical experiment on the hydrogen economy can be observed. The experiment is more generally called a test-bed, which is made possible by Iceland’s small society and unique natural environment. Iceland has developed hydrogen energy policies, and corresponding activities have provided researchers with experimental experiences. This paper sheds light on Iceland’s challenge from a sociotechnical system viewpoint, which emphasizes the importance of sociotechnical experiments in the early stage, i.e. niche level. Preconditions and conditions of the experiment are analyzed, together with the presentations of observed phenomena, such as articulation of visions and development of networks. A critical review on the Icelandic experiment should provide us with useful lessons and policy implications for improving hydrogen energy activities not only in R&D but also especially in demonstration and deployment.

Space-time variability in environmental thermal properties and snail thermoregulatory behaviour

1. Behavioural adaptations of ectotherms to thermally heterogeneous environments are still overlooked in the literature despite the fact that organismal behaviour could enhance survival in the warming world. This is particularly critical in the intertidal where most ectotherms live at, or near to the upper limit of thermal tolerance. 2. This study investigated (i) the environmental factors determining the body temperatures of the intertidal gastropod Nerita atramentosa, (ii) the space–time variability in environmental and individual body temperatures and (iii) the potential variability in N. atramentosa thermoregulatory behaviours, i.e. microhabitat selection and aggregation. 3. Thermal imaging was used to assess the body temperatures of N. atramentosa and surrounding substrata over two seasons (autumn and summer), at two shore levels (low- vs. high-shore levels) within two habitats of different topographic complexity (rock platform and boulders) on the same rocky shore. 4. Snail body and substratum temperatures were significantly and positively correlated within each habitat at both seasons. Substratum temperature may thus be considered as a primary driver of body temperatures of organisms that attach to a substratum. Substratum temperature and other variables such as solar irradiance critically need to be integrated in climate-change models that use single climatic variables (e.g. air temperature) that are not necessarily correlated with individual body temperatures in nature. 5. The high space–time variability in both substratum and body temperatures reinforces the growing evidence that small spatial scale variations may surpass those observed at larger spatial scales. 6. Nerita atramentosa thermoregulatory behaviour under high thermal stress appeared to be habitat specific. 7. The small spatial scale heterogeneity in environmental and individual temperatures and in thermoregulatory behaviours has stressed the need to focus on body temperature patterns at the niche level and to integrate the organismal behaviour in climate-change models.